Z wobble is a common problem in 3D printing that causes the printed layers to shift or wobble along the Z-axis, resulting in a distorted or uneven surface. Z wobble can be caused by various factors, such as loose screws, bent rods, misaligned couplers, or poor quality lead screws. To fix Z wobble, you need to identify the source of the problem and make sure that all the components of the Z-axis are properly aligned, tightened, and lubricated. Here are some steps you can take to reduce or eliminate Z wobble:

• Check the screws that hold the Z-axis rods and lead screws in place. Make sure they are not too loose or too tight. You can use a hex wrench to adjust them if needed.
• Check the rods and lead screws for any bends or damage. If they are bent, you can try to straighten them using a hammer or a vise. If they are damaged, you may need to replace them with new ones.
• Check the couplers that connect the lead screws to the stepper motors. Make sure they are not cracked or worn out. You can use a screwdriver to tighten them if needed.
• Check the alignment of the Z-axis rods and lead screws. They should be parallel to each other and perpendicular to the X-axis and Y-axis. You can use a ruler or a level to measure the angles and distances between them.
• Lubricate the rods and lead screws with a suitable grease or oil. This will reduce the friction and noise and improve the smoothness of the Z-axis movement.